Fatigue Testing

Expansion Joint Fatigue Testing

Three specimens of the TechStar Single Bar Modular Bridge Expansion Joint (MBEJ) with welded stirrups were tested in fatigue according to the requirements of the NCHRP-402 Report, the AASHTO Bridge Construction Specifications and AASHTO LRFD 1998 Bridge Design Code.  The fatigue testing was carried out at the Structures Laboratory at École de Technologie Supérieure, University of Quebec.

Welded Stirrups
Test results were used to produce an experimental fatigue curve of the stirrup details with all points located above the AASHTO Fatigue curve for Category C Welds. Hence it can be concluded that the fatigue resistance of the welded stirrup connection detail of the TechStar MEJS Single Bar System is compatible with (and qualifies for) the fatigue Category C of the AASHTO LRFD 1998 Bridge Design Code.

Attached Plate Details
The test results produce six (06) S-N points, all of them located above the AASHTO Fatigue curves for Category B’. Hence, on the basis of these points, it may be assumed that the fatigue resistance of the center-beam at the location of the attachment plate connection detail of the TechStar Single Support Bar MEJS is compatible with the fatigue Category B’ of the AASHTO LRFD 1998 Bridge Design Code.

Furthermore, the study concluded that the TechStar Single Support Bar MEJS can be modeled by simple 1-D beam element models with reasonable accuracy.  A complete report is available upon request.

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